The objective of this project is to study several aspects of some neuropeptides which are thought to have clinical implications in several psychiatric disorders such as schizophrenia, catatonia, depression and mania. Some of these peptides are also known to have a central role in the mediation of pleasurable states, motor behavior and several endocrine and autonomic functions. The specific aims of our project are the following: 1. The characterization and purification of the enzymes involved in the synthesis of enkephalin and their localization in the brain and other tissues. 2. The characterization of the enkephalin precursors and the measurement of the effects of neuroleptics and other psychotropic drugs on the synthesis and turnover rate of enkephalins. The long-term goal of the proposed research is to obtain some of the basic knowledge for the determination of the neuropsychiatric significance of enkephalins and beta-endorphin and to determine the involvement of these neuropeptides in psychopathological conditions and in the mediation of the therapeutic response to neuroleptics and to other psychotropic drugs.